Effect of Combined Exercise Training on Heart Rate Variability and Aerobic Capacity of Boys with Type 1 Diabetes

Background and Objective: Dysfunction in the autonomic nervous system can cause cardiovascular complications in patients with type 1 diabetes (T1D). The present study aimed to investigate the effect of combined exercise training on heart rate variability (HRV-5min), aerobic capacity (VO2max), and glycemic index in boys with T1D. Materials and Methods: In this semi-experimental research, 24 adolescent boys with insulin-dependent T1D and 12 healthy boys of the same age with an age range of 12 to 18 years were selected and divided into three groups: healthy, control diabetic, and exercise diabetic. The exercise diabetic group performed combined exercises for 12 weeks, three sessions a week. Blood variables and cardiac variables were measured 48 h before and 72 h after the intervention. Dependent t-tests and one-way analysis of variance were used for statistical analysis. Results: After the intervention, a significant increase in VO2max variables, high frequency HRV (HF) and a significant decrease in Resting Heart Rate Variables (HRrest), the ratio of low frequency to high frequency HRV (LF.HF) and glycemic index were observed in the exercise diabetic group (P<0.05). In addition, in the inter-group analysis of the difference between the pre-test and post-test results, a significant difference was observed in VO2max, HRrest, HF, LF.HF, and blood glucose indices in the exercise diabetic group compared to the healthy and diabetic control groups (P<0.05). Conclusion: Our results showed that combined exercise training along with insulin-dependent treatment could help to strengthen the cardiovascular system (HRV) in boys with T1D by improving the function of the parasympathetic branch of the autonomic nervous system.